Pressure-responsive device and mounting means therefor



June 10, 1958 E, wooo 2,838,071

PRESSURE-RESPONSIVE DEVICE AND MOUNTING MEANS THEREFOR Filed May 18. 1954 INVENTOR Louvarc E. Wood.

ATTORNEY PRESSURE-RESPONSIVE msvrcn AND MOUNTING MEANS THEREFOR Louvan E. Wood, Glen Arm, Md., assignor to Bendix Aviation Corporation, Baltimore, Md., a corporation of Delaware 7 Application May'18 1954, Serial No. 430,699 7 Claims. (Cl. 137-784) An example of a pressure-responsive device with which the present invention is concerned, is that type comprised of one or more relatively thin plates or shells formed of material such as Beryllium copper. Where a plurality of plates are employed, they are usually of dished or concavo-convex formation and joined at their circumferential edges to define a sealed chamber, which may be evacuated and/or charged withv a suitable fluid, to obtain a desired response. A problem which confronts manufacturers and users of pressure-responsive devices of the type specified is the error factor resulting from vibration; and an object of this invention is to provide a pressure-responsive device of the diaphragm. type and mounting means therefor which will prove helpful toward a solution of such problem.

Another object is to provide a diaphragm type pressure responsive device and a peripheral edge mounting means therefor which will enable the diaphragm plate or plates to have limited movement or give in a plane normal to the direction of response of the said plate or plates without introducing disturbing or opposing forces to such response, while at the same time the device as a whole will be held against movement in an axial plane.

Another object is to provide a mounting means for a pressure-responsive device of the type specified which will facilitate location of the device in cramped spaces with out hindering the effective response thereof.

A'further object is to provide a mounting for a pressureresponsive cell of the diaphragm type which will not only Fig. 3 is a plan view of the complete unit of Fig. 2; and V Fig. 4 is a view in elevation illustrating how the device of Figs. 2 and 3 may be used to control electric circuitry. I

Referring to Fig. l, a pressure sensitive device or cell is generally indicated at it comprises a pair of reverselydished, annularly corrugated diaphragm shells (although it could consist of a single shell if so desired) joined together at their meeting edges, defining a peripheral bead as at 11. In the center of the upper shell is a stud or like member 12, which serves as a means for operatively connecting the said shell to a part to be controlled. If de sired, a similar member 12 may be connected to the lower shell of the device.

The cell 10 is shown as being mounted in an opening 13, formed in a plate 14. It will be noted that the shell is suspended at three points, preferably spaced 120 degrees apart, by resilient leaf spring members 15, 15' and 15", each of which has one end fixed to the plate 14, as by soldering, the opposite end projecting free and being formed with a notch 16, adapted to receive the bead 11.

Preferably, the free end of each spring is reversely bent into a partial U-shape, as indicated at 17, to provide a better grip on the head 11.

It will be obvious that the diaphragm plates are free for normal movement in response to changes in pressure while at the same time they are held against movement bodily in the axial direction but may have limited movement in the plane of the plates or cell in response to expansion and contraction of the supporting means for the cell and/ or the material of which the plates are made. However, such latter movement does not cramp or place a strain on the pressure-responsive portions of the diaphragm walls. The effects of vibration on a diaphragm mounted in this manner will be substantially nullified, since same will be absorbed by the resilient mounting means therefor and will not materially affect the response characteristics of the diaphragm. Both sides of the cell are clear of mounting obstructions and hence may be used as requirements dictate. For example, one side may be used to sense pressure and the other side used as a seal, or both sides may be used to sense pressure and transmit a force as a function of changes in pressure. Thus the improved mounting arrangement as herein disclosed has all the advantages of the encircling rigid-type edge mounting while at the same time it eliminates all of the disadvantages of the latter type of mounting.

Figs. 2 and 3 show a modified arrangement with respect to that'shown in Fig. 1. In this instance the cell is indicated at 20; it comprises a pair of reversely-dished and corrugated diaphragm plates or shells 20 and 20", joined at their meeting edges and defining a bead as at 21. The members 22 and 23 connected to the upper and lower plates or shells correspond to the stud 12 of Fig. 1.

Thecell 20 is supported by three annular members 24, 25 and 26, preferably located at approximately 120 degrees apart and secured to an annular supporting ring 27 by screws 24', 25 and 26'. Preferably, the supporting members 24, 25 and 26 are annular in shape and the screws 24', 25' and 26 are located eccentrically with respect to each member so as to permit the membersto :be rotated for adjustment purposes. Each of the mounting members is formed with an annular groove 28, adapted to receive the edge or bead 21 of the cell 20. By loosening any one of the screws 24, 25 or 26', the coacting supporting member may be rotated to locate the cell 20 at a predetermined position and to also exert the desired amount of grip on the bead 21. If desired, the members 24, 25

and/or 26 may be made of resilient material, such as rubber, to obtain the cushioning action afforded by the resilient supporting members 15, 15' and 15" of Fig. 1. It will also be noted that the diaphragm shells 20' and 20 are free to move axially in opposite direction in response to changes in pressure while at the same time the cell is supported firmly in a restricted space.

Fig. 4 illustrates how a pressure-responsive cell, mounted as disclosed herein, may be used to control different electric circuits or components as a function of changes in pressure. In this instance, the ceILindicated at 30, comprises a pair of reversely-dished diaphragm shells joined at their meeting edges, at which point a bead 31 is defined. Here, as in Figs. 2 and 3, there are three supporting members, located degrees apart, two of which are visible and indicated at 32 and 32', each of said members being formed with an annular groove, as indicated at 33. The supporting members 32 and 32 are anchored to an annular ring or plate 34, having a central opening 35. Posts or rods 36 and 37 are connected to the upper and lower plates of the diaphragm. On the outer end of post or rod 36 is an armature 38, movable to vary the coupling effect between the primary P and the secondaries-S and S of an input transformer, the secondaries being arranged in phase-opposed relation. On the outer end of.

post or rod 37 is core. member 39, movableto varythe 1 inductance in a coil 39. When the cell 30 is subjected to changes in pressure, the upper and lower shells will move in: response-to saidbhanges and reposition thearmature 318 and core 39.

The difierent embodiments of theinvention shown and describedherein are to. be consideredas illustrative rather than restrictive, itbeing understood that limited-changes in construction and design may bemade toadapt-the improved device. to ditferentinstallations within the scope of the-invention as defined by the appended claims.

Whatis claimed and desired to be secured by United States Letters Patentis:

1. In combinatioma pressure responsive devicehaving walls defining an expansible chamber including a discshaped diaph-ragmfor-med of relatively :thin metallic material, and means for supporting said device, comprising a plurality of resilient members located at spaced points around theperipheral portion of said diaphragm in gripping engagement with said portion at said spaced points only.

2. In combination, apressure-responsive device having H said device. comprising supporting elements located at spaced points around the periphery of said diaphragms and gripping said pheripheral edges at the line of jointure thereof at said spaced points only.

4. A device as claimed in claim 3 wherein said supporting elements are spaced at approximately 120 apart 7 and resiliently--engage-said edges.

5. In combination, a pressure-responsive device comprising a pair'o'f reversely-dished disc-shaped diaphragms of relativelyrhinmetallic. material joined at their peripheral edges and defining -a fluid enclosure therebetween, and supporting means for said device including at least three resilientelements arranged in spaced relation around the periphery of said diaphragms in gripping engagement with said edges at the line-of jointure thereof.

6. A device as claimed in claim 5 wherein said supporting elements consist of spring members formed of a strip of. resilient metallic material, each member having a. pqrtion thereofisprung into engagement with said peripheral. edges.

7.. The combination. as .claimed in claim 5 wherein said supportingelements consist of strips of resilient metallic material each having a portion thereof sprung into engagement with said peripheral edges and formed with a slot to.

receive saidedges. 7

References Cited in the file of this patent UNITED STATES-PATENTS Johnson Oct. 3. 1950 

